Ink composition and image forming method

Abstract

An inkjet ink composition includes: (a) particles of a polymer compound having at least one reactive functional group selected from the group consisting of an epoxy group, an acetoacetoxy group, a halomethyl group, a carboxylic acid anhydride, an amino group, a hydroxyl group, a phenolic hydroxyl group, and a carboxy group; (b) a reactive compound having a functional group that reacts with the reactive functional group of the (a) particles of the polymer compound by energy application; (c) a coloring agent; and (d) a water-soluble organic solvent.

What is claimed is: 
     
         1 . An inkjet ink composition comprising:
 (a) particles of a polymer compound having at least one reactive functional group selected from the group consisting of an epoxy group, an acetoacetoxy group, a halomethyl group, a carboxylic acid anhydride, an amino group, a hydroxyl group, a phenolic hydroxyl group, and a carboxy group;   (b) a reactive compound having a functional group that reacts with the reactive functional group of the (a) particles of the polymer compound by energy application;   (c) a coloring agent; and   (d) a water-soluble organic solvent.   
     
     
         2 . The inkjet ink composition according to  claim 1 , wherein the polymer compound has a hydrophilic group. 
     
     
         3 . The inkjet ink composition according to  claim 1 , wherein the polymer compound includes a repeating unit having a hydrophilic group as a copolymerizable component, and a content ratio of the repeating unit having a hydrophilic group with respect to a total of repeating units that form the polymer compound is within a range of from 3% by mass to 50% by mass. 
     
     
         4 . The inkjet ink composition according to  claim 1 , wherein a number average molecular weight of the (b) reactive compound is less than 500. 
     
     
         5 . The inkjet ink composition according to  claim 1 , wherein a number average molecular weight of the (b) reactive compound is 500 or more. 
     
     
         6 . The inkjet ink composition according to  claim 1 , wherein the (b) reactive compound is water-dispersible. 
     
     
         7 . The inkjet ink composition according to  claim 1 , wherein the (b) reactive compound is water-soluble. 
     
     
         8 . The inkjet ink composition according to  claim 1 , wherein a particle diameter of the (a) particles of the polymer compound is from 100 nm to 300 nm. 
     
     
         9 . The inkjet ink composition according to  claim 1 , wherein the energy application is at least one selected from the group consisting of heating and active ray irradiation. 
     
     
         10 . The inkjet ink composition according to  claim 1 , wherein the reactive functional group of the (a) particles of the polymer compound is at least one selected from the group consisting of an epoxy group, a carboxy group, and an acetoacetoxy group, and the functional group of the (b) reactive compound that reacts with the reactive functional group of the (a) particles of the polymer compound by energy application is different from the reactive functional group, and is at least one selected from the group consisting of an epoxy group, a carboxy group, and an amino group. 
     
     
         11 . An image forming method comprising:
 applying the ink composition according to  claim 1  onto a recording medium; and   applying energy to the ink composition that has been applied onto the recording medium.   
     
     
         12 . The image forming method according to  claim 11 , wherein the applying energy is performed by heating the ink composition that has been applied onto the recording medium. 
     
     
         13 . The image forming method according to  claim 11 , further comprising removing a solvent including a water-soluble organic solvent that is included in the ink composition that has been applied onto the recording medium, either simultaneously with the applying energy or before the applying of energy.